Drift scooter

0001This application is a divisional of co-pending U.S. patent application Ser. No. 12/750,163, filed Mar. 30, 2010, herein incorporated by reference.

BACKGROUND

0002Non-motorized foot board scooters are known in the art. These scooters generally include a front wheel aligned with a back wheel, with each of the wheels being attached to a frame. The frame generally comprises a flat surface located between the two wheels for the rider to stand on and a steering assembly rising vertically from the front or leading end of the frame. The steering assembly is attached at one end to the front wheel for front wheel steering of the scooter and terminates at the other end in handle bars for the rider to use to steer the scooter. Forward movement of these non-motorized foot board scooters is normally achieved by the rider taking one foot off the flat surface and pushing against the ground with the foot removed from the flat surface to begin forward movement of the scooter. In order to negotiate turns on the typical scooter the rider turns the front wheel while leaning into the turn such that the front and rear wheels track along an arc in the usual manner. The turning style of the typical scooter is similar to that of riding a bicycle, for example.

0003While enjoyable to ride, the typical scooter design merely provides the same predictable cornering experience that is well known in the art. Accordingly, there exists a demand for a scooter that provides a new and exciting cornering sensation that enhances the rider's enjoyment in riding the scooter.

SUMMARY

0004Described herein are various embodiments of a drift scooter. Generally, the drift scooter comprises a longitudinal frame including opposed leading and trailing end portions. The scooter may include a deck extending along at least a portion of the frame. Preferably, the top surface of the deck includes a convex portion.

0005A steering assembly is pivotably disposed on the leading end portion and includes a transverse member with two wheels rotatably supported on opposite ends of the transverse member. A stem is fixed in perpendicular orientation relative to the transverse member and a handlebar is connected to the stem. The leading end portion includes a head tube with at least one bearing housed therein, the bearing including an inner race attached to the stem and an outer race attached to the head tube, wherein the inner and outer races include interfering projections that limit the rotation of the stem with respect to the frame.

0006A rear wheel assembly is pivotably disposed on the trailing end portion, wherein the wheel assembly pivots about an upwardly extending pivot axis. The pivot axis is inclined forwardly with respect to the leading and trailing end portions. The pivot axis is inclined forwardly with respect to vertical between about 5 and about 25 degrees. The rear wheel assembly may include a caster pivotable about the pivot axis and is preferably biased toward a centered position, wherein the caster is aligned with a centerline of the frame. The wheel assembly preferably includes an end stop that limits the extent to which the caster can pivot.

0007A resilient member is connected between the frame and a leading portion of the caster. The resilient member may be in the form of an extension spring, for example. Means for adjusting the tension of the extension spring may also be included. Preferably, a caster guard is disposed on the frame forward of the caster. The caster guard may also contain at least a portion of the extension spring therein.

0008Also contemplated is a method for inducing oversteer in a scooter during a turn on a surface. The method comprises providing the scooter with a rear wheel assembly pivotably disposed about a pivot axis on a trailing end portion of the scooter, the rear wheel assembly including a wheel rotatably mounted on an axle. The rear wheel assembly is biased toward a centered position, wherein the wheel is aligned with a centerline of the scooter. The axle is positioned rearward of the pivot axis such that a lateral load generated against the wheel by the surface during the turn causes the rear wheel assembly to pivot away from the centered position in a direction opposite the turn thereby inducing oversteer. The method may further comprise limiting the extent to which the rear wheel assembly can pivot. The scooter may further include a deck and the method further comprising maintaining the deck at a generally level attitude relative to the surface during the turn.

0009The foregoing and other features, utilities, and advantages of the drift scooter will be apparent from the following more particular description of the embodiments as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of a drift scooter and together with the description, serve to explain the principles and operation thereof. Like items in the drawings are generally referred to using the same numerical reference.

<figref idref="DRAWINGS">FIG. 1</figref> is a perspective view of a scooter according to an exemplary embodiment;

<figref idref="DRAWINGS">FIG. 2</figref> is a right side elevation view of the scooter shown in <figref idref="DRAWINGS">FIG. 1</figref>;

<figref idref="DRAWINGS">FIG. 3</figref> is a bottom plan view of the scooter shown in <figref idref="DRAWINGS">FIGS. 1 and 2</figref>;

<figref idref="DRAWINGS">FIG. 4</figref> is a partial front view of the scooter showing the steering assembly partially exploded;

<figref idref="DRAWINGS">FIG. 5</figref> is a partial bottom view of the steering assembly shown in <figref idref="DRAWINGS">FIG. 4</figref> with the transverse member removed for clarity;

<figref idref="DRAWINGS">FIG. 6</figref> is an enlarged partial side view of the frame and rear wheel assembly;

<figref idref="DRAWINGS">FIG. 7</figref> is a cross-section of the rear wheel assembly taken about line <b>7</b>-<b>7</b> shown in <figref idref="DRAWINGS">FIG. 6</figref>;

<figref idref="DRAWINGS">FIG. 8A</figref> is a schematic representation of the drift scooter as viewed from above illustrating the scooter traveling straight;

<figref idref="DRAWINGS">FIG. 8B</figref> is a schematic representation of the drift scooter as viewed from above illustrating the initiation of a right turn;

<figref idref="DRAWINGS">FIG. 8C</figref> is a schematic representation of the drift scooter as viewed from above illustrating oversteer induced by the pivoting rear wheel assembly; and

<figref idref="DRAWINGS">FIG. 8D</figref> is a schematic representation of the drift scooter as viewed from above illustrating the steering assembly turned to counteract oversteer induced by the pivoting wheel assembly.

DETAILED DESCRIPTION

0022Described herein is a drift scooter that provides a new and exciting cornering sensation enhancing a rider's enjoyment. The design induces oversteer in the scooter as it turns thereby providing the sensation that the scooter is sliding or drifting. The sliding or drifting sensation simulates a feeling of extreme speed. Furthermore, controlling the drift through counter-steering provides an entertaining challenge for the rider.

0023<figref idref="DRAWINGS">FIG. 1</figref> illustrates a drift scooter <b>5</b> according to an exemplary embodiment. Scooter <b>5</b> includes a frame <b>10</b> with a deck <b>20</b> disposed thereon. Pivotably supported on a leading end portion <b>12</b> of frame <b>10</b> is a steering assembly <b>30</b>. Steering assembly <b>30</b> includes handlebar <b>32</b> with a pair of handgrips <b>31</b>′ and <b>31</b>″ disposed on opposite ends thereof. Handlebar <b>32</b> is secured to steering tube <b>34</b> by clamp <b>36</b>. A transverse member <b>42</b> is connected to the handlebars <b>32</b> via the steering tube <b>34</b>. Rotatably supported on opposite ends of transverse member <b>42</b> are front wheels <b>38</b>′ and <b>38</b>″. Rear wheel assembly <b>60</b> is rotatably disposed on trailing end portion <b>14</b> of frame <b>10</b>. It can be appreciated from <figref idref="DRAWINGS">FIG. 1</figref> that the scooter disclosed herein is preferably a three wheeled vehicle having two wheels located on the leading end of the scooter and a single wheel located on the trailing end of the scooter, A rider may stand on deck <b>20</b> while grasping handgrips <b>31</b>′ and <b>31</b>″. As with a conventional scooter, the rider may propel the scooter by kicking with one foot. It should also be understood that as a rider rotates handlebar <b>32</b> relative to frame <b>10</b> the entire steering assembly <b>30</b>, including front wheels <b>38</b>′ and <b>38</b>″, also rotates in order to steer the scooter as desired.

0024As perhaps best shown in <figref idref="DRAWINGS">FIG. 2</figref>, deck <b>20</b> includes a convex portion <b>22</b>, which provides a contoured surface for the rider to brace against during drifting maneuvers which are explained more fully below. Leading end portion <b>12</b> includes head tube <b>15</b> through which handlebars <b>32</b> are connected to transverse member <b>42</b>. With reference to both <figref idref="DRAWINGS">FIGS. 1 and 2</figref>, frame <b>10</b> arcuately extends upwards to meet head tube <b>15</b>, thus lowering the center of gravity of the scooter. Frame <b>10</b> also includes wheel guard <b>18</b> disposed in front of rear wheel assembly <b>60</b>. Wheel guard <b>18</b> protects rear wheel assembly <b>60</b> from impact with curbs and other obstacles which could potentially cause damage to rear wheel assembly <b>60</b>. As shown here, wheel guard <b>18</b> is a ramp shaped member capable of deflecting obstacles away from the mounting portion of rear wheel assembly <b>60</b> such that obstacles may slide over the wheel guard <b>18</b> as well as rear wheel assembly <b>60</b> without directly impacting the wheel assembly. With further reference to <figref idref="DRAWINGS">FIG. 3</figref>, wheel guard <b>18</b> also has a tubular construction which may also house a centering spring and tension adjuster for the rear wheel assembly <b>60</b> as explained more fully below.

0025Also shown in <figref idref="DRAWINGS">FIG. 3</figref>, frame <b>10</b> includes opposed leading and trailing end portions, <b>12</b> and <b>14</b> respectively, with a longitudinal portion <b>13</b> extending therebetween. Extending transversely from longitudinal portion <b>13</b> is a plurality of rib supports <b>16</b> that support deck <b>20</b>. In this embodiment, deck <b>20</b> is secured to rib supports <b>16</b> with a plurality of fasteners <b>24</b>. Frame <b>10</b> may be formed of metal such as steel or aluminum. Deck <b>20</b> may be formed from plastic, wood, or light metals, or the like.

0026<figref idref="DRAWINGS">FIG. 4</figref> is a partial exploded view illustrating how steering assembly <b>30</b> is assembled with head tube <b>15</b>. Stem <b>44</b> is fixed in perpendicular orientation relative to transverse member <b>42</b>. Stem <b>44</b> may, for example, be welded to transverse member <b>42</b>. When assembled, stem <b>44</b> extends through head tube <b>15</b> and is secured in place with bearing nut <b>57</b>. Stem <b>44</b> includes a lower inner bearing race <b>48</b> which receives lower bearing <b>53</b>. Head tube <b>15</b> includes lower and upper outer bearing races <b>52</b> and <b>54</b> respectively. Lower bearing race <b>52</b> receives lower bearing <b>53</b> and upper outer bearing race <b>54</b> receives upper bearing <b>55</b>. Bearing nut <b>57</b> includes an inner race which engages upper bearing <b>55</b>. Bearing nut <b>57</b> engages threads <b>46</b> disposed on the upper end of stem <b>44</b>. The arrangement of inner and outer bearing races and upper and lower bearings is well known in the art and is typically used on bicycles. However, in this case lower inner bearing race <b>48</b> is preferably permanently attached to stem <b>44</b> by welding or otherwise so that it cannot rotate with respect to stem <b>44</b>. Similarly, lower outer bearing race <b>52</b> is fixed to head tube <b>15</b> with a rivet <b>59</b> so that it cannot rotate with respect to head tube <b>15</b>.

0027Referring now to <figref idref="DRAWINGS">FIG. 5</figref>, which shows the lower bearing races <b>48</b> and <b>52</b>, lower bearing race <b>48</b> includes a pair of outwardly extending protrusions <b>43</b>′ and <b>43</b>″. Lower outer bearing race <b>52</b> includes a pair of inwardly extending protrusions <b>58</b>′ and <b>58</b>″. One of ordinary skill in the art will recognize that as stem <b>44</b> is rotated relative to head tube <b>15</b> protrusions <b>43</b>′ and <b>43</b>″ will interfere with protrusions <b>58</b>′ and <b>58</b>″. Thus, the left and right steering rotation of the steering assembly <b>30</b> relative to frame <b>10</b> is limited. Briefly returning to <figref idref="DRAWINGS">FIGS. 1 and 2</figref> it can be appreciated that the rotation of steering assembly <b>30</b> is advantageously limited in order to prevent wheels <b>38</b>′ and <b>38</b>″ from interfering with frame <b>10</b> or deck <b>20</b>.

0028<figref idref="DRAWINGS">FIG. 6</figref> illustrates a partial side view in partial cross-section of the rear wheel assembly <b>60</b> and a resilient member in the form of an extension spring <b>80</b> along with associated mounting components and features. In this embodiment, rear wheel assembly <b>60</b> is in the form of a caster which includes caster frame <b>64</b>, rear wheel <b>62</b>, and an axel <b>66</b> that supports rear wheel <b>62</b> in frame <b>64</b>. Rear wheel assembly <b>60</b> is pivotably mounted on a spindle <b>72</b> which extends from trailing end portion <b>14</b>. Caster frame <b>64</b> is mounted to spindle <b>72</b> with a suitable fastener <b>68</b>. As can be appreciated in <figref idref="DRAWINGS">FIG. 6</figref>, rear wheel assembly <b>60</b> pivots about axis “A” which is inclined forwardly with respect to the leading and trailing end portions of frame <b>10</b>. Axis “A” may be inclined at between about 5 and about 25 degrees, but preferably at about 18 degrees. The inclination of axis “A” has a tendency to center rear wheel assembly <b>60</b> along longitudinal frame portion <b>13</b>. Thus, the rear wheel assembly is biased towards a centered position where the caster is aligned with a longitudinal axis of the frame. Also, by angling the caster, side to side motion of the caster tends to cause forward propulsion. This may be accomplished by weaving the scooter back and forth, for example.

0029Extension spring <b>80</b> acts on caster frame <b>64</b> in order to further bias the rear wheel assembly <b>60</b> toward the centered position. Extension spring <b>80</b> includes hook portions <b>82</b> and <b>84</b> which connect the spring between frame <b>10</b> and caster frame <b>64</b>. Hook portion <b>82</b> connects to ear <b>63</b> (see <figref idref="DRAWINGS">FIG. 7</figref>) and hook portion <b>84</b> connects to frame <b>10</b> via tension adjuster <b>90</b>. Tension adjuster <b>90</b> includes mounting bracket <b>92</b> which is attached to frame <b>10</b> through an opening in wheel guard <b>18</b>. Threadably engaged through mounting bracket <b>92</b> is an adjustment screw <b>94</b> which has a connector loop <b>96</b> rotatably disposed thereon. Hook portion <b>84</b> is connected to loop <b>96</b> so that as adjustment screw <b>94</b> is threaded in or out with respect to mounting bracket <b>92</b> the tension of extension spring <b>80</b> is accordingly decreased or increased. It should be appreciated that while the resilient member has been described here as an extension spring other structures for biasing the caster to the centered position may be employed. For example, a torsion spring may be disposed about spindle <b>72</b> which engages the caster frame <b>64</b>. Also, it is contemplated that compression springs could be arranged to bias the rear wheel assembly <b>60</b> toward the centered position. As mentioned above, wheel guard <b>18</b> houses extension spring <b>80</b> and tension adjuster <b>90</b>. Thus, wheel guard <b>18</b> also protects the tensioning components.

0030With reference to <figref idref="DRAWINGS">FIG. 7</figref>, the rotation of rear wheel assembly <b>60</b> about axis “A” is limited by an end stop <b>74</b> extending from frame <b>10</b>. End stop <b>74</b> extends into slot <b>65</b> which is formed in caster frame <b>64</b>. As can be seen in the figure, slot <b>65</b> extends arcuately around a portion of the circumference of the caster frame. Thus, rotation of the rear wheel assembly <b>60</b> is limited by the length of the arcuate slot <b>65</b>.

0031Having described the structure of the drift scooter, the operation of the scooter can now be better appreciated. <figref idref="DRAWINGS">FIGS. 8A-8D</figref> are schematic representations of the scooter as viewed from above during various stages of a right hand drift turn. In <figref idref="DRAWINGS">FIG. 8A</figref> scooter <b>5</b> is shown traveling straight with the transverse member <b>42</b> and front wheels <b>38</b>′ and <b>38</b>″ oriented perpendicular to frame <b>10</b> while rear wheel assembly <b>60</b> is centered with respect to frame <b>10</b>. <figref idref="DRAWINGS">FIG. 8B</figref> shows scooter <b>5</b> at the point of initiating a right-hand turn. Transverse member <b>42</b> and front wheels <b>38</b>′ and <b>38</b>″ are rotated to the right via the handle bars. As the scooter begins to turn, a lateral load or centripetal force “F” is exerted on contact patch <b>67</b> of rear wheel <b>62</b>. It should be understood that contact patch <b>67</b> is offset from pivot axis “A” such that the centripetal force “F” acting on contact patch <b>67</b> causes rear wheel assembly <b>60</b> to rotate around pivot axis “A” such as shown in <figref idref="DRAWINGS">FIG. 8C</figref>. Thus, depending on the amount of centering bias exerted on rear wheel assembly <b>60</b> the wheel assembly will rotate about pivot axis “A” as the scooter generates enough centripetal force to overcome the centering bias. As shown in <figref idref="DRAWINGS">FIG. 8C</figref>, oversteer is induced in the scooter as rear wheel assembly <b>60</b> pivots in a direction opposite to the turn. As explained above with respect to <figref idref="DRAWINGS">FIG. 6</figref>, the tension in extension spring <b>80</b> may be adjusted. Increasing the tension in extension spring <b>80</b> will decrease the amount of oversteer and decreasing the tension will increase the amount of oversteer. Finally, as shown in <figref idref="DRAWINGS">FIG. 8D</figref> transverse member <b>42</b> and wheels <b>38</b>′ and <b>38</b>″ are rotated away from the turn (to the left) in order to compensate for the oversteer induced by rear wheel assembly <b>60</b>. This technique of compensating for oversteer in a vehicle is often referred to as counter-steering. Convex portion <b>22</b> of deck <b>20</b> mentioned above provides a contoured or banked surface for the rider to stand against during a drift as described above. Note that the three wheeled configuration of the scooter with two front wheel facilitates the drift maneuvers described above while maintaining deck <b>20</b> at a generally parallel or level attitude with respect to the riding surface.

0032Methods relating to the above described drift scooter are also contemplated. The methods thus encompass the steps inherent in the above described mechanical structures and operation thereof. Broadly, one method could include inducing oversteer in a scooter during a turn on a surface. More specifically, the method could comprise providing the scooter with a rear wheel assembly pivotably disposed about a pivot axis on a trailing end portion of the scooter, the rear wheel assembly including a wheel rotatably mounted on an axle. The rear wheel assembly being biased toward a centered position, wherein the wheel is aligned with a centerline of the scooter. The axle is positioned rearward of the pivot axis such that a lateral load generated against the wheel by the surface during the turn causes the rear wheel assembly to pivot away from the centered position in a direction opposite the turn thereby inducing oversteer. The method may further comprise limiting the extent to which the rear wheel assembly can pivot. The scooter may further include a deck and the method further comprising maintaining the deck at a generally level attitude relative to the surface during the turn.

0033Accordingly, the drift scooter has been described with some degree of particularity directed to the exemplary embodiment. It should be appreciated, though, that the present invention is defined by the following claims construed in light of the prior art so that modifications or changes may be made to the exemplary embodiments without departing from the inventive concepts contained herein.